Endometrial metaplasia as a source of atypical glandular cells in cervicovaginal smears

Cytohistological correlation of abnormal cervicovaginal smears indicates that endometrial metaplasia may be associated with the presence of atypical glandular cells. Seven patients with histologically confirmed endometrial metaplasia had atypical glandular cells in cervicovaginal smears; five smears were interpreted as being suspicious for endometrial adenocarcinoma. Most of the patients (5/7) were postmenopausal (mean age = 61.3 years), and three of seven patients had abnormal vaginal bleeding. The corresponding endometrial tissue specimens demonstrated various combinations of eosinophilic, papillary, squamous, and tubal metaplasia; in one case tubal metaplasia occurred in association with an endometrial polyp. Cytologic features noted in the cervicovaginal smears from all seven patients were similar and included small clusters of atypical glandular cells in an inflammatory background. Intracytoplasmic vacuoles were often present, and a moderate degree of aniosonucleosis was noted. Enlarged glandular nuclei contained finely granular chromatin and distinct nucleoli. The differential diagnosis of atypical glandular cells includes endometrial hyperplasia and well-differentiated endometrial adenocarcinoma. The atypical cells associated with endometrial metaplasia were characterized by a relatively low N:C ratio and evenly distributed chromatin. In contrast, the cells of endometrial carcinoma typically demonstrate increased N:C ratios and irregularly distributed chromatin.